Asingleparticle-inductivelycoupledplasmamassspectrometric(SP-ICP-MS)methodwas established to detect the size distribution and number concentrations of silver nanoparticle ( AgNPs) in dilute aqueous solution. The optimal dwell time was 3 ms to reduce possibility of two or more particles entering into detector simultaneously. An iterative algorithm was applied to distinguish AgNPs as outliers from baseline and dissolved metal ion signal if the measured intensity was beyond five time standard deviation of whole data. Size distribution and number concentration of three commercial silver nanoparticle dispersions ( nominal diameters of 30, 50, 100 nm) were determined using SP-ICP-MS. The result of SP-ICP-MS is accurately similar to the transmission electron microscopy ( TEM) , indicating that SP-ICP-MS is able to size silver nanoparticles. The particle size detection limit is 25 nm and the limit of number concentration is 8 × 104 particles/L in dilute solution. Tap water added with silver nanoparticle was tested to obtain a similar size distribution and number concentration. This method is simple, fast and highly sensitive, which can be used to investigate risk assessment of silver nanoparticle in aqueous environment and monitor silver nanoparticle in drinking water.

Objective:To investigate the clinical, imaging, etiological and prognostic features of patients with infarctions in different locations of the medulla oblongata.Methods:Patients with acute medullary infarction hospitalized at Tianjin Huanhu Hospital from July 2017 to July 2022 were included. The risk factors, clinical manifestation, stroke mechanism and 90-day prognosis of these patients were analyzed retrospectively.Results:Among the 256 patients enrolled, 150 (58.6%) had lateral medullary infarction (LMI), 106 (41.4%) had medial medullary infarction (MMI). The most frequent clinical manifestation of patients with LMI was dizziness (84.7%,127/150). And motor disorders (83.0%,88/106) was the most frequent clinical manifestation of patients with MMI. LMI lesions were mostly located in the middle (42.7%,64/150) and MMI lesions were mostly located in the upper (60.4%,64/106) medulla oblongata, with statistically significant difference (χ 2=47.53, P<0.001). Large artery atherosclerosis (LAA) was the main stroke mechanism in LMI and MMI [57.3%(86/150) vs 56.6%(60/106)]. Early neurological deterioration was more common in MMI (25.5%,27/106) and less common in LMI (7.3%,11/150), with statistically significant difference (χ 2=16.17, P<0.001). At discharge, more patients with MMI showed poor prognosis in short term [45.3% (48/106) vs 24.0% (36/150), with statistically significant difference (χ 2=12.76, P<0.001)] and even long term at 90-day follow-up [33.0% (35/106) vs 12.7% (19/150), also with statistically significant difference (χ 2=15.48, P<0.001)] than those with LMI. A total of 10 patients (4.0%, 10/256) developed respiratory failure during hospitalization, including 7 patients with LMI (4.7%, 7/150) and 3 patients with bilateral MMI (2.8%,3/106). Early neurological deterioration ( OR=3.38, 95% CI 1.25-9.10, P=0.016) and LAA (compared with small artery occlusion) ( OR=3.08, 95% CI 1.13-8.37, P=0.028) were independent risk factors for poor prognosis in MMI. Age ( OR=1.01, 95% CI 1.01-1.17, P=0.026) and early neurological deterioration ( OR=20.19, 95% CI=2.63-155.06, P=0.004) were independently correlated with poor outcome in LMI. Conclusions:LMI and MMI had similar etiology and significant differences in clinical manifestations, early neurological deterioration and prognosis. Further classification of medullary infarction was of great significance for diagnosis, treatment and prognosis evaluation.

Atherosclerosis is a complex pathological condition resulting from lipid deposition， chronic inflammatory responses， and fibrosis， with a prolonged disease course and multifactorial etiology. Based on the traditional Chinese medicine （TCM） theory of accumulation syndrome， atherosclerosis can be classified under this category， with its pathogenesis involving phlegm， blood stasis， deficiency， and accumulation. This paper proposed a stage-based intervention strategy using the four therapeutic principles of "attacking， supplementing， dispersing， dissipating"， and divided into six stages based on the pathological progression， including the stage of accumulation before formation， the stage of accumulation already formed， the stage of nucleus accumulation， the stage of nucleus accumulation decay， the stage of nucleus accumulation consolidation， and the stage of severe stenosis of nucleus. At different stages， the intervention focuses on reinforcing healthy qi and consolidating the root， tonifying the kidneys and spleen， dispersing and removing turbidity， removing phlegm stagnation， promoting qi circulation， dispersing accumulations and removing stasis， attacking accumulation and expelling stasis， directing the turbid downward and dispersing accumulation， and treatment would be adjusted based on specific symptoms， which provides a theoretical framework for the prevention and treatment of atherosclerosis with TCM.